Letterboxd also has:
- accounts from high profile users such as the aforementioned Sean Baker & Jonathan Rosenbaum and many others.
- accounts held by numerous lower profile but equally serious film critics
- far livelier discourse, with a good culture of legitimate reviewing, formulating canons & in depth exploration of esoteric regions of film.
- almost every function of ICM plus ratings, a much better site design, a more efficient twitter style followers/following function, additional profile customisation, detailed statistics and regular community polls, articles & interviews conducted by staff
- rarer experimental/older non-English language/VR-adjacent films are much easier to add to Letterboxd due to the comparative ease of adding things to TMDB. TMDB also handles non-English films much better, by not forcing alphabet romanisation & keeping surname/given name order consistent to country of origin for cast/crew.
- somewhat meaningful yearly popularity charts & more functions for filtering and ordering lists
And many other things not coming to mind right now.
I’m not trying to bag on ICM though, I actually prefer it.